1. Field of the Invention
The present invention relates to a filter cloth cleaning device for a filter press wherein cleaning liquor is sprayed onto the filter cloth from a spray tube with a multiplicity of spray nozzles, which is adapted to move along and substantially parallel to each filter cloth.
2. Description of the Prior Art
There have been proposed quite a number of cleaning devices of the type, in which the spray tube is pivoted downwardly into place between filter cloths covering each opened pair of filter plates and the cleaning liquor is sprayed from the spray tube onto the aforesaid filter cloths for cleaning thereof. A device having its spray tube long and large, as disclosed, for example, in West German Pat. No. 1611097, which features the possibility of cleaning the entire surface of the filter cloth through simple movement of the spray tube between the opened pair of opposed filter cloths as aforesaid, has a drawback of requiring a large swing diameter for the spray tube as it is pivoted downwardly into place between adjacent filter cloths and also of requiring a large space around the filter press. Moreover, its spray tube in its waiting position above the filter plates projects substantially beyond the side of the filter press, this interfering with or limiting utilization of the spaces along the sides of or above the filter press.
A solution to the aforesaid problem was proposed by the filter cloth cleaning device of U.S. Pat. No. 4,129,137, in which a spray tube carrier carrying a spray tube erect below filter plates of the filter press is caused to travel both-ways in front of the filter cloth.
This system has an advantage of enabling installation above the filter press of the filter cloth oscillating device for imparting oscillation to the filter cloth for shaking off the filter cake (cake depositing on the filter cloth after filtration), utilizing the ample space available there, Since the cleaning device of the aforesaid U.S. patent, however, has to be kept waiting where it is not exposed to the shower of cake until completion of shaking off of the filter cake, the time required for cleaning is increased, resulting in lowering of the filter press' working efficiency.
The cleaning device of the German patent has arranged on a carrier 33 adapted to be movable on rails laid above and longitudinally of filter plates a cleaning liquor spray tube 14 and a bracket 36 of a work cylinder 6 for lifting and lowering thereof tiltably pivoted by means of a fulcrum shaft 32. The above bracket 36 has its position controlled by a tilting cylinder 34 and its piston 36. Indicated by solid line in FIG. 1 of this patent is the position the device assumes before starting of cleaning, and thereafter the work cylinder 6 operates to alternately lift and lower the cleaning liquor spray tube 14 in its level position for the filter cloth or filter plate to be sprayed with the cleaning liquor.
When the aforesaid bracket 36 is tilted by the tilting cylinder 34, the cleaning liquor spray tube as well as its work cylinder and guides moves into the waiting position indicated by dotted lines in FIG. 1.
Unlike the device disclosed above, the cleaning device of the present invention is contrived to be small in the space it occupies above the filter press.
The cleaning device of the U.S. Pat. No. 4,129,137 comprises a first carrier 12 adapted to be movable on rails under a group of filter plates and a movable unit 11 adapted to be movable thereon. A cleaning liquor spray tube 10 is disposed vertically on the movable unit 11 and is adapted to move sideways and alternately in front of the filter cloth or filter plate for cleaning (by spraying) thereof. Its relationship with the present invention is already described above.